Radioactive source storage container with elongated flexible means for removing sources from the container



R. J. PREST Feb. 4, 1964 3,120,613

RADIOACTIVE souRcE STORAGE CONTAINER WITH ELONGATED FLEXIBLE MEANS FoR REMOVING SOURCES FROM THE CONTAINER Filed Feb. 13, 1956 am 2 W fizmsvzz ar 306572 (I Prgyfi 07.1 @5122 JJ! J22 1117:

United States Patent 3 120 613 RADKQACTEVE SQUR UE STi)RAGE (IONTAENER WITH ELGNGATED FLEXIBLE IWEANS FOR REMQVENG lfiURQES FRGM THE CGNTAENER Robert .1. Prest, Concord, Mass, assignor to Technical Uperations, inc, Arlington, Mass., a corporation of Delaware Filed Feb. 13, 1956, Ser. No. 565,137 4 Claims. (Ci. 256-106) The present invention relates to shielded containers for and to procedures of transporting and changing, sources of radioactive material.

Objects of the invention are to provide a source changing system for use with devices which employ radioactive material that is confined within capsules that can be attached to elongate carriers such as cables, for example of the type disclosed in my copending application Serial No. 494,786 of March 16, 1955, now Patent No. 2,916; 628; to provide such a system which permits safe and easy transport of such sources; which permits safe insertion thereinto and storing therein of two sources of radioactive material, one source at a time, such as a fresh source in one portion and an exhausted source in another portion; which permits adaptation for carrying more than two sources either at the same time or at different times at ditlerenflit portions thereof; which safely prevents escape of radiation from a source stored therein; which permits easy and safe exchange of sources by unskilled personnel; and which permits the locking of sources stored therein during shipment; to provide a source changing system which occupies a minimum of space and shielding material such as lead; and to provide such a system which generally advances the art of storing, transporting and handling radioactive material.

The following brief summary indicates the nature and substance of the invention in various aspects, for attaining the above objects.

Devices for transporting and charging sources of radioactive material according to the invention have a shielding container with two or more adjacent openings prefer =ably on a flat side thereof; within the container they have two or more tube-like means or cavities each closed at one end and communicating at the other end with a respective opening, such that the closed ends are located approximately near the center of the container with each tube being sufiiciently curved to obstruct a straight path of escape or radiation from a source located near the closed end of the tube towards the end that communicates with the respective opening; at the openings are preferably provided means for passing source mounting members into a tube and for closing the tube opening.

in an important practical aspect, the capsule is attached to an elongate auxiliary carrier that reaches from the closed end of the tube to its open end, so that closutre of the open tube end will secure the capsule at the closed, safe end of the tube.

With such devices, sources of radioactive material can be exchanged for example by transporting the container with a fresh source inserted at the safe, closed end of one of the tubes, by inserting a decayed source on its carrier into the other tube, and by changing the carrier from the decayed source to the fresh source whereupon the fresh source can be withdrawn from the container for use, whereas the decayed source can be transported, after closing the tube wherein it is contained on location.

The tubes can be arranged essentially parallel to each other with the closed ends near the center of the shielding container and with the open ends preferably removed far enough from each other such that closing and locking means can be conveniently applied.

3,120,513 Patented Feb. 4, 1564 ln another important practical aspect, the shielding container is nearly spherical with a frusto-conical body super-imposed thereon, the fiat or face of the superimposed body containing the openings for the tubes and provisions for closing the tubes and for confining a source at the closed end of the tube. Instead, the tubes can have the shape of semi-circles or ellipses with adjacent tubes curved in opposite direction such that the closed ends are close to each other near the center of the shielding container, with the other ends emerging nearly parallel at a fiat face of the container.

Instead of being nearly spherical, the container can have the general shape of a cylinder with the openings of the tubes in one of the flats or faces of the cylinder.

Means for securing sources have, according to an additional aspect of the invention, a bridge member that is somewhat distant from and parallel to the face for the openings and has, in perforations thereof, a tubular adapt er member for each opening; these tubular members can have threads on the outside which correspond to threads of a sealing tube which is open towards its respective opening of a source confining tube, whereas the other end of the sealing tube is closed and has provisions, such as a head with an inside threaded annular recess that fits the thread of its adapter tube.

These and other objects, and aspects of the nature of the invention will appear from the herein presented description of two typical embodiments illustrating its novel characteristics, its mode of operation, and its practical possibilities. These refer to drawings in which FIG. 1 is a cross section of a device according to the present invention, taken through the axes of the openings of the two tubes of the device;

FIG. 2 is an axial cross section similar to FIG. 1 but in a plane perpendicular to the section plane of FIG. 1, and through the opening of one of the tubes;

FIG. 3 is a schematical axonometric View, with part of the shell broken away, showing the general arrangement of another embodiment of the invention; and

FIG. 4 is a top view corresponding to FIG. 3, showing the two tubes in dotted lines.

in FIGS. 1 and 2, the numeral 11 denotes a shell made from steel of suitable gage, depending upon the size of the container which again depends upon the radiation intensity of the source to be confined therein; inch stock will be ordinarily sufiicient for the purpose. The roughly spherical shell 11 has a four sided opening 12 defined by the edges 12.1, 12.2, 12.3 and 12.4 to which are welded sheets 15.1 to 15.4. A frusto-conical body 15 is formed by the sheet 15.3 which is wrapped around the spherical shell body 11 and welded thereto at the tangential circle indicated at '16. A fiat sheet 17 closes this structure. As indicated in FIG. 1, the container is filled with shielding material such as lead, which is poured in through an opening near to the apex ridge formed by walls 15.3 and 15.4 as shown in FIG. 2. The space which is enclosed by sheets 15.4 and 15.3 can remain empty since it is beyond the effective shielding radius defined by the spherical shell body 11.

Two tubes 21 and 22 pass through openings of the plate 15.4 and are with their open ends 212, 22.2 fastened to the opening 23, =24 of the fiat cover plate 17. These tubes are bent as indicated in FIG. 2 in order to prevent escape of radiation from the closed ends 21.1 and 22.1. The open or communicating ends 21.2 and 22.2 are spaced in order to permit the application of closing means as will be described hereinbelow. As shown in the drawings, the communicating ends of the two tubes open perpendicularly into the outer face of plate 17.

As a means for mounting of closing and sealing provisions, a bracket 31 is fastened to the fiat plate 17. The

bridge portion 31.1 of the bracket 31 is parallel to the plate 17 and has two openings into which are fastened two adapter tubes or nipples 32.1 and 32.2 which are threaded on the outside of their outer ends, as indicated at 52.2 and 32.3. Into the adapter tubes fit sealing tubes 35.1 and 35.2 each of which has at one end a shank with a deep recess or bore 36.1, 36.2 and at the other end a sealing tube cap 37.1 and These caps have depending lips that form annular recesses with inside threads corresponding to the outside threads 32.2 and 32.3 of the adapter tubes 32.1 and 32.2.

The above described parts are joined, so far as the assembly is to be permanent, by means of conventional welding techniques.

FIGS. 1 and 2 indicate, within tube 22, a source capsule S which is connected, for example by swaging, to an auxiliary or mounting carrier, such as a flexible cable M. This mounting cable has at its other end a connector C which permits convenient disengagement from a handling carrier, such as another flexible cable of considerably greater length (not shown), either by relatively rotating the two cables or with the aid of a simple tool. The cable M is just long enough to fill-between the encapsulated source S and the connector C-the tube 21 or 22 reaching from the closed end 21.1 or 22.1 through the open end into and touching, with the connector C, the bottom of the recess 36.1 or 36.2 of the sealing tube 35.1 or 35.2.

A typical application of a source changing system as above described serves for the replacement of an encapsulated radioactive source that is decayed to a point where it has become undesirable for use, but is still active enough to present a health hazard. In a typical example, this operation takes place as follows. A shielding container according to the invention serves as the shipping means for a new source which may be represented by capsule S in tube 22, attached to its auxiliary cable M which has at its other end a connector C as above described. The source S is secured in the container by means of the sealing tube 35.2 which, during shipping, may be secured to the bracket 31 by means of a wired lead water seal, indicated at W of FIG. 1.

The container is brought near to the installation where sources of fissionable material are in use and an old source which is mounted similar to the just described new Source is with the aid of suitable safety provisions injected into the tube 21 of the container. When the old source capsule is safely within the end portion 21.1, its connector is unfastened and the old source is secured by means of the sealing tube 35.1.

The sealing tube 35.2 is then removed, the cable M is with its connector C fastened to a handling carrier cable, and the capsule S is from a distance withdrawn from the container and inserted into the radiation instrument where it is to be used.

The sealing tube 35.1 can be secured with a seal W and the old source is ready for shipment.

While the source confining tubes 21, 22 according to FIGS. 1 and 2 are arranged essentially equidistant with the communicating ends parallel and somewhat bent and spread apart to provide a distance accommodating the sealing tubes with their caps, the embodiment according to FIGS. 3 and 4 employs identical tubes as distinguished from the tubes of FIGS. 1 and 2 which are in right-hand, left-hand relation and not interchangeable. FIGS. 3 and 4 also indicate a somewhat differently shaped, essentially cylindrical container or shell 51 with two flat end faces one of which is indicated at 57.

The tubes 61 and 62 are essentially identical but mounted with opposite curvatures such that the closed ends 61.1, 62.1 are approximately at the center of the container while the communicating ends 63.1, 63.2 are appreciably separated without making special bends necessary. As clearly indicated in the figures, the tube parts that are adjacent the closed ends are essentially parali lel. Sealing and closing provisions can be arranged on the end face or platform 57, in a manner similar to that described above with reference to FIGS. 1 and 2.

It will now be evident that more than two tubes can be provided in either embodiment for example by replacing the spherical shell of FIGS. 1 and 2 with a cylindrical container having an axis perpendicular to the drawing surface of either FIGS. 1 and 2. Cylindrical shells according to FIGS. 3 and 4 accommodate a plurality of tubes arranged in axial symmetry, with their communicating ends arranged in a circle on plate 57.

Devices according to either FIGS. 1 and 2, or FIGS. 3 and 4 can be arranged within parallelepipedal shells if more than a few tubes have to be accommodated, although one important aspect of the inventionespecially in the embodiment according to FIGS. 1 and 2is then lost, namely optimum compactness and economy of sealing material.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. A device for transporting and changing sources of radioactive material of the type in which the radioactive material is held at the end of an elongated flexible carrier comprising, a unitary shielding body, a changer head mounted on said body, said head being spaced from said body and having two similar connectors each adapted for coupling to a tubular conduit, two channels within said body each closed at one end and communicating at the other end to the outside through a respective opening in said body, each of said openings being in register with but spaced from one of said connectors, said closed ends being approximately near the center of said body and each channel means being curved such as to obstruct any straight path from near its closed end to its outside end.

2. A device for transporting and changing sources of radioactive material of the type in which the radioactive material is held at the end of an elongated flexible carrier comprising, a unitary shielding body, a changer head mounted on said body, said head having two similar connectors each adapted for coupling to a tubular conduit, said connectors being mounted in a plate holding them spaced from said shielding body, two channels within said body each closed at one end and communicating at the other end to the outside through a respective opening in said body, each of said openings being in register with one of said connectors, a removable sealing element supported in each of said connectors, each sealing element having a tubular projection directed toward and in register with the channel opening which is in register with its supporting connector, said closed ends being approximately near the center of said body and each channel means being curved such as to obstruct any straight path from near its closed end to its outside end.

3. Device according to claim 2, combined with an elongated flexible carrier which has at one end a holder for radioactive material and at the other end detachable means for coupling to another similar carrier, said carrier being of a length such that with said holder seated at the closed end or" one of said channels said coupling means is located in the space between said plate and said shielding body and within the tubular projection of the associated sealing element, whereby by detachment of said sealing element said coupling means of said carrier can be manipulated in said space for attachment to another carrier via the associated connector.

4. A device for transporting and changing sources of radioactive material of the type in which the radioactive material is held at the end of an elongated flexible carrier comprising, a unitary shielding body, a changer head mounted on said body, said head being spaced from said body and mounting a connector for coupling to a tubu- 6 lat conduit, a channel within said body closed at one end References Cited in the file of this patent and communicating at the other end to the outside UNITED STATES PATENTS through an opening in said body in register with but 2,514,909 Strickland July 11, 1950 spaced from said connector, said channel being curved 2,716,705 Zinn Aug, 30, 1955 to obstruct any straight path from near its closed end to 5 2 79 164 Untel-myer July 2 1957 its outside end and having its closed end approximately FOREIGN PATENTS at the center of said body, said space between said head 1,079,640 France Dec 1, 1954 and said body being sufiicient to permit manipulation of a coupling element between two elongated flexible car- 10 L OTFHER REFERENCES riers extending from such tubular conduit and from said gg g q i I; g gi 2: gg g vg i g si y em 0 u is mg mp, n channel respectwely' New York, N.Y., pages 144-147. 

1. A DEVICE FOR TRANSPORTING AND CHANGING SOURCES OF RADIOACTIVE MATERIAL OF THE TYPE IN WHICH THE RADIOACTIVE MATERIAL IS HELD AT THE END OF AN ELONGATED FLEXIBLE CARIER COMPRISING, A UNITARY SHIELDING BODY, A CHANGER HEAD MOUNTED ON SAID BODY, SAID HEAD BEING SPACED FROM SAID BODY AND HAVING TWO SIMILAR CONNECTORS EACH ADAPTED FOR COUPLING TO A TUBULAR CONDUIT, TWO CHANNELS WITHIN SAID BODY EACH CLOSED AT ONE END AND COMMUNICATING AT THE OTHER END TO THE OUTSIDE THROUGH A RESPECTIVE OPENING IN SAID BODY, EACH OF SAID OPENINGS BEING IN REGISTER WITH BUT SPACED FROM ONE OF SAID CONNECTORS, SAID CLOSED ENDS BEING APPROXIMATELY NEAR THE CENTER OF SAID BODY AND EACH CHANNEL MEANS BEING CURVED SUCH AS TO OBSTRUCT ANY STRAIGHT PATH FROM NEAR ITS CLOSED END TO ITS OUTSIDE END. 